Copper Beech Farm, this 12-bedroom waterfront estate on 50 acres in wealthy Greenwich, has been sold for $120 million. Even though that’s $70 million under Copper Beech Farm’s initial listing price, real estate agent David Ogilvy tells the Greenwich Time he believes the sum is the most ever paid for a residential property in the United States.

NEW HAVEN, Conn. — Connecticut’s Gold Coast is living up to its name, with a record $120 million sale of a waterfront estate in Greenwich leading an increase in sales of homes for more than $10 million.

Five homes sold this year for more than $10 million in Greenwich, according to the assessor’s office. Another home just sold and four others listed above $10 million are under contract, compared with only one under contract by this time last year and none sold, said Mark Pruner, a sales executive with Berkshire Hathaway HomeServices.

He attributed the rise in sales to the jump in the stock market and accumulated bonuses in recent years.

“There is more confidence in the economy and people have more money to spend,” Pruner said.

Some sales also could stem from concerns by buyers about New York City Mayor Bill de Blasio, Pruner said. In testimony to Connecticut lawmakers about legislation concerning estate and gift taxes, he said only three houses sold in Greenwich for more than $10 million in the first seven months of last year, but eight suddenly sold starting in August, around the time de Blasio became the leading candidate for mayor on a platform of higher taxes on those earning more than $500,000.

“A lot of wealthy people in New York thought they had a target on their back with Mayor de Blasio in office,” Pruner said. “It’s unclear as to how big it is, but it is certainly something discussed among buyers.”

The mayor proposed universal pre-kindergarten funded with a tax hike on the wealthy, a plan that was defeated in Albany. The program will instead be funded with money from the state budget.

Real estate agent David Ogilvy, who was the listing and selling agent on the $120 million home, also said he believes concerns about de Blasio are a factor in some buyers choosing Greenwich, though he didn’t think it was for the buyers of the record sale.

“They don’t know what he is going to come up with next,” Ogilvy said.

The home sales are good for Connecticut because they show wealthy buyers want to live in the state and they are major contributors to taxes, charities and business startups, Pruner said.

A 12-bedroom waterfront estate on 50 acres sold for $120 million this month in what Ogilvy has called the most ever paid for a residential property in the United States. That was quickly followed on by a $14.3 million sale Monday of a 52-acre estate in nearby New Canaan.

Those two sales within a week are “quite amazing,” said Barbara Cleary, whose real estate company sold the New Canaan property after listing it for about five years.

“I think there is new interest in investing in real estate,” Cleary said. “I think the higher end is getting more activity.”

The New Canaan property had been owned by Huguette Clark, a reclusive heiress who died at 104 in 2011. She bought it in 1951 but never moved in, Cleary said.

“This was really sort of the crown jewel of the town,” Cleary said.

The property was originally listed by another broker for $34 million, Cleary said.

Buyers were not disclosed in the sales to limited liability companies.

While sales of homes above $10 million rose, sales between $5 million and $10 million in Greenwich fell from last year, Pruner said. There were five such sales in the first quarter of this year, down from 15 in the same period last year, he said.